Translations, progress bar fallback, lowercasing

+ Added translations into English for ``cy``, ``es`` and ``na'vi``,
  to ensure that all possible current languages are catered for.
+ Added ``background-color`` rule to progress bars on ``project`` to
  ensure that they are always visible.
+ Forced lowercase for more of the ``project`` page 'cos it looks nice
  (although that's an opinion).
- Removed redundant text shadow rule.